1. Field of the Invention
This invention relates in general to concrete support foundations constructed in-situ particularly useful for supporting tall, heavy and/or large towers which may be used to support wind turbines, power lines, street lighting and signals, bridge supports, commercial signs, freeway signs, ski lifts and the like. More specifically, the pile anchor foundation of the present invention is useful in supporting such towers in clay or other fine grain soils which are water bearing and/or too weak to stand or maintain the dimensions of an excavation formed to receive a concrete foundation. Such soils can be found in the midwest region of the United States.
2. Description of Related Art
My earlier U.S. Pat. Nos. 5,586,417 and 5,826,387, entitled Tensionless Pier Foundation and Pier Foundation under High Unit Compression, respectively, and my pending U.S. patent application Ser. No. 10/067,999, filed Feb. 8, 2002 and entitled Perimeter Weighted Foundation for Wind Turbines and the like which is a continuation of U.S. patent application Ser. No. 09/671,282, now abandoned, disclose post-tensioned concrete tower foundations, the disclosures of which are incorporated herein by reference as if fully set forth. The prior art cited in these patents and application may also be relevant to the pile anchor foundation of this invention.